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State profile · EPA SDWIS + UCMR5

Delaware Drinking Water Quality

460 public water systems serve 1,083,630 people across Delaware, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.

460
Water systems
9,105
Total violations
74.8%
Systems w/ a violation
71.4%
PFAS detection rate

The verdict

Across Delaware, 344 of 460 water systems (74.8%) carry at least one EPA violation, and 25 of 35 UCMR5-tested systems show PFAS.

9,105
Total EPA violations on record
50%
Health-based (MCL / treatment)
74.8%
Systems with ≥1 violation
71.4%
UCMR5 PFAS detection rate
Water Systems
460
Total Violations
9,105
Violation Rate
74.8%
PFAS Detection
71.4%
25 of 35 tested

Violation Composition

How Delaware's 9,105 violations break down by type, per EPA SDWIS classification.

Health-based (4,582) Monitoring/Reporting (4,523)
Metric Value Share
Public water systems460-
Population served1,083,630-
Total violations9,105100%
Health-based violations4,58250.3%
Systems with violations34474.8%
PFAS detection rate25 of 3571.4%

Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.

Largest Water Systems

Artesian Water Company
Newark, DE · 231,114 served
31 violations
Wilmington Water Department
Wilmington, DE · 107,976 served
30 violations
Veolia Water Delaware, Inc
Wilmington, DE · 100,495 served
46 violations
Rehoboth Pump District (Tui)
Dover, DE · 81,417 served
9 violations
Bethany Bay Pump District
Dover, DE · 51,000 served
11 violations
Newark Water Department
Newark, DE · 40,000 served
42 violations
Dover Water Department
Dover, DE · 39,491 served
47 violations
Dewey Beach Water Department
Frankford, DE · 31,000 served
4 violations
Rehoboth Beach Water Department
Rehoboth Beach, DE · 25,000 served
Artesian Southern Sussex Regional
Newark, DE · 18,015 served
11 violations
Middletown Water Department
Middletown, DE · 17,700 served
26 violations
Camden Pump District
Dover, DE · 17,208 served
7 violations
Garrison Lake Pump District
Dover, DE · 13,467 served
12 violations
Sussex Shores Water Company
Bethany Beach, DE · 12,450 served
9 violations
Bethany Beach Water Department
Bethany Beach, DE · 12,000 served
21 violations
Smyrna Water Department
Smyrna, DE · 11,813 served
7 violations
Dover Air Force Base
Dover, DE · 11,000 served
17 violations
Long Neck Water Company
Long Neck, DE · 11,000 served
20 violations
Milford Water Department
Milford, DE · 9,800 served
6 violations
Church Creek (Awc)
Newark, DE · 9,654 served
8 violations

Most Violations

#1 Forest Park Millsboro
358
#2 Briarwood Manor MHP Pittsford
168
#3 Hilltop Trailer Park Denton
165
#4 Pine Ridge Mobile Home Park Seaford
134
#5 Granada Mobile Home Court Magnolia
127
#6 Fish Hook Mobile Home Park Georgetown
126
#7 Bethany Crest LLC Clarksville
112
#8 Holiday Acres, LLC Rehoboth
102
#9 The Little Campus, LLC Newark
99
#10 Country Corners Market Milton
98
#11 Oak Grove Estates Dover
97
#12 Delaware State Fair Harrington
97
#13 Law Mobile Home Park Camden
96
#14 O a Newton and Sons Inc Bridgeville
94
#15 Mountaire-Millsboro Millsboro
93

Counties in Delaware

New Castle
76 systems · 541,043 served · 1,173 violations
Sussex
251 systems · 382,938 served · 4,772 violations
Kent
133 systems · 159,649 served · 3,160 violations
View all 460 systems in Delaware →

Drinking Water Guides

Is Your Tap Water Safe?

How to interpret water quality reports and know when to take action.
PFAS in Drinking Water

What forever chemicals are, EPA testing results, and 2024 standards.
Check Your Water System

Step-by-step guide to finding and understanding your local water data.

Frequently Asked Questions

How many water systems are in Delaware? ▼
Delaware has 460 public water systems serving approximately 1,083,630 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Delaware? ▼
Delaware has 9,105 total drinking water violations on record, with 4,582 classified as health-based violations. 74.8% of water systems in the state have at least one violation.
Has PFAS been found in Delaware drinking water? ▼
Of 35 water systems tested for PFAS in Delaware, 25 had PFAS detected, a 71.4% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Delaware water systems? ▼
Delaware's violation rate is 74.8%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Delaware water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

Data Sources & Methodology

Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.

Read our methodology - how this data is sourced, computed, and verified.

Related

All states → | Most violations → | Compare counties →
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.